JPS5814470A - Dry battery - Google Patents

Abstract

PURPOSE:To increase very high rate discharge performance by adding sodium perchlorate (NaClO4) to an electrolyte and using fine manganess dioxide having a mean particle size (Dp) of 10mum or less. CONSTITUTION:Adding sodium perchlorate to an electrolyte shows the largest additive effect, and the corrosion rate of zinc in this electrolyte is substantially reduced. In the high temperature storage, no occurrence of stop corrosion and no deposit of insoluble crystal on zinc surface are observed, therefore, it acts as a corrosion inhibitor. Increase of internal impedance during low rate continuous discharge is somewhat reduced. A special effect of NaClO4 on very high rate discharge performance is especially noticeble when high active electrolytic manganese dioxide is used as a composition of wet cathode mix. The finer particle size of the electrolytic manganese dioxide is preferable, and about 10mum particle size indicates clear effect but more fine particle size gives more good results.

Description

DETAILED DESCRIPTION OF THE INVENTION This wA relates to improvement S2 of electrolyte solution for dry batteries, and is aimed at improving rapid discharge characteristics of batteries.

General 6: The electrolyte of a Leclanche dry battery is a saturated solution of ammonium chloride containing an appropriate amount of zinc chloride. When the water inside evaporates and dissipates, the same phase that should be precipitated with C2 is only a dendritic (II!4oJ) and is in a composition region that does not form double salts such as (znoA-am*cJ). It is a feature. Generally, the electrolyte contains 35-551 ammonium chloride and 5-20% zinc chloride. When a dry battery using such an electrolyte is discharged, the following electromotive reaction causes the formation of poorly soluble electrolytes. Forms diamine complex salts.

2Mn01 + 2HH4Cjノ+Kn →2MziO
OH+ zn(NIB)'g (32g) Outer edge C of this cyanide complex salt expanded anode mixture: Dense resistance layer (Hara-L
ayer), which contributes to the deterioration of the rapid discharge characteristics of Lecrancier dry batteries.

On the other hand, the electrolyte of a zinc chloride dry battery is an unsaturated solution consisting of a zinc chloride solution containing either no ammonium chloride or a very small amount of ammonium chloride. It consists of a homogeneous solution containing 10% zinc chloride and 10% or less ammonium chloride.

The main reaction when discharging a battery using such an electrolytic solution is as shown in the following equation, and the main reaction is that insoluble basic chloride is produced as a reaction product.

8Mn01 + Zn0J, @◆8H@0+4zn-
+8Mn0OH+ZnCJB・4Zn(OH)@This basic chloride precipitate does not form a dense resistance layer like the above-mentioned diamine complex salt, so it may cause a sudden increase in the internal resistance of the battery or cause significant diffusion obstruction due to the reaction product C2. This does not occur, and a rapid discharge characteristic comparable to that of ammonium chloride dry battery S can be obtained. Since this reaction consumes water inside the battery, it is also the main reason for increasing the leakage resistance of zinc chloride dry batteries. Although it has the effect of slightly lowering the leakage resistance, the presence of a large amount lowers the leakage resistance, so it is practical to add it in a range of about 0.5 to 4.0 inches. Zinc chloride-based dry batteries have excellent rapid discharge characteristics, so they have recently been replacing ammonium chloride-based Lucranci dry batteries, but recently they have been used in various applied devices with motor drive mechanisms. With the development of technology, there is a need to further improve the heavy load characteristics of dry cell batteries, which are the power source.

This invention mainly uses an electrolytic solution consisting of an aqueous zinc chloride solution containing salts such as zinc chloride or a small amount of ammonium chloride.
When adding sodium perchlorate (Na0j04), the average particle size (Ep) as manganese dioxide was 10μ.
Concerning dry batteries using fine manganese dioxide with a size of less than m,
The purpose is to improve the ultra-heavy load discharge characteristics of batteries.

The super-heavy load discharge referred to here refers to a discharge in the breakdown current region where a large load is applied, such that the utilization rate of anode manganese dioxide is 10% or less in a battery under normal battery structure and manufacturing conditions. say. For example, in the case of an R-6 type cell (AA type), it refers to a discharge condition in which the average discharge current is continuously consumed at around IA or higher.〇 Modification of zinc chloride electrolyte that meets the above objective C2. Various electrolytes were investigated as agents, and special C: various inorganic salts of oxyhalogen acids were investigated, but the best results were obtained with sodium perchlorate.

First, regarding oxyhalogen acids [general formula HXOn] that combine with metal ions and other cations to form salts, halogen (X) is C! In cases where F, Br, or
Salts such as chlorite and hypozinc acid F'1c10 cannot be used because they have strong oxidizing power and are unstable to manganese dioxide.In the end, only the salt of perchloric acid acjo4 can be used in a relatively stable state. there were.

Next, the results of an investigation using two cations w1f constituting perchlorate will be explained.

First of all, the alkali metal salts C and then Os, R
In the case of perchlorate No. 13, C- cannot be put to practical use because of its low solubility in zinc chloride solution. On the other hand, in the case of L1 salt, even when 12 was added, no effect of improving super heavy load discharge characteristics (hereinafter referred to as synergistic effect) was observed. Regarding salts other than alkali metal salts, a synergistic effect was observed in #iZn salt, but
It was not observed with other NT14 salts, Mg salts, etc. When zinc perchlorate was added, a synergistic effect was observed in the region of relatively high concentration change in C;9, but the electromotive force of the cell using the electrolyte chamber with this composition was normal in the model test cell described later. It shows the electric potential, but when used in a dry pond, it is about 70 m.
V11Q' shows a low value. Furthermore, when the corrosion of zinc was measured in this electrolyte, although the corrosion rate of the known zinc chloride-based electrolyte ε nilbenzinc was small, uneven spot spots were generated on the zinc surface, and some The precipitation of microscopic, colorless, poorly soluble crystals that were difficult to discern with the naked eye was observed. This phenomenon was similarly confirmed during storage of actual R-6 type dry batteries.

In contrast, when IJium is added, the synergistic effect is greatest, and the C-
It was found that the corrosion rate of zinc in a known zinc chloride dry electrolyte solution was suppressed by C nylvane equivalent I:. Furthermore, even when stored at high temperatures, no pitting on the zinc surface or precipitation of hardly soluble crystals was observed, and as a result, it functioned as a corrosion inhibitor (TOR rather than HH). Furthermore, as an unexpected incidental effect, an effect of suppressing the rise in internal impedance during light load continuous discharge to some extent was also observed. The light load discharge capacity is mainly controlled by the active material content C2, and is not very affected by the internal resistance, but the so-called pulse group 1i, in which a heavy load is intermittently superimposed for a short time during a light load discharge, is controlled by the active material content C2.
At tC, the above effect is significant because it is strongly influenced by internal resistance. Some of these effects, especially the synergistic effect on super-heavy load discharge characteristics, have a FiMac concentration of 1.
When the weight is about 5-5, it is hardly observed, and when it exceeds it, the properties are deteriorated, so it is important to note that sufficient effects can be expected in the region below the FiIO weight, and in this case, the Zn (J concentration is In case of known zinc chloride electrolyte f without adding acid salt (24 to 35% by weight) #
: It has been experimentally shown that it is effective in a slightly lower range (15 to 30 degrees).

Such a lifting load discharge characteristic is reached! vinegar! 180104
Is the unique effect of the manganese dioxide that makes up the wet anode mixture? I: is observed in all cases of natural manganese dioxide, activated manganese dioxide, chemically synthesized manganese dioxide, and electrolytic manganese dioxide. However, when used in combination with highly active electrolytic manganese dioxide, Special 1: is noticeable, and in the case of the above various manganese dioxides other than electrolytic manganese dioxide, I: itself has a relatively low activity, so The effect under severe conditions is relatively small compared to the case of electrolytic manganese dioxide.

Furthermore, in the case of di-electrolytic manganese dioxide, its ultra-uniload characteristics improve as the particle size becomes finer.

In addition, when an electrolyte containing NaClO2''J or zn(ato+)a is used, compared to the case where a known Zn01B-based electrolyte is used, the combination with fine electrolytic mankan dioxide is more difficult. It was experimentally confirmed that the effect is even greater.

As is well known, manganese dioxide having an average particle diameter (Ep) of about 20 to 40'pm is generally used as manganese dioxide for dry batteries. The inventor compared several types of electrolytic manganese dioxide with an average particle size in the range of 2 to 70 μm, and found that the finer the particle size, the better, and that a clear effect was shown at around 10 μm, and that finer particle sizes showed two better effects. It was found that the results were shown. However, when electrolytic manganese dioxide is refined, secondary agglomeration occurs due to its surface activity 1-, so it is difficult to economically obtain powder with a Dp of less than the micron level using ordinary pulverization methods. As mentioned above, the synergistic effect when using finely divided electrolytic manganese dioxide and a zinc chloride electrolyte to which sodium perchlorate is added will be explained below using Examples.

Examples of the present invention will be described below.

First, Table IC2 shows the composition and physical properties of some electrolytic solutions including known electrolytes constituting this invention. Composition (parts by weight) and physical properties of the zinc-based electrolytic solution 0 or B indicates one of the typical solution compositions among the electrolytic solutions containing sodium perchlorate that constitute the present invention 9◇c; D, x
This is an example in which other inorganic perchlorates were added that had no lri effect, and Ll 0704 e HH+ c
jo*-Mg (Of 04) is added.

0, D, ]! The liquid composition of l is similar to Bl2 for comparison.The reason for this is that the amount required to prevent hydrolysis differs depending on the electrolyte.OF is an electrolyte containing Zn(ClO2)g, and this shows a synergistic effect at a relatively high addition rate, and shows one of the representative liquid compositions.

Table 2I shows the composition of the wet 114 anode mixture prepared using the electrolyte of class 69 above. Component 1 in Table 2
1! Ml is electrolytic manganese dioxide with an average particle size of 2'ppm (D), EMg is electrolytic manganese dioxide with a particle size of 5 μm, hBli is acetylene plaque at 5zarJ, zinc chloride, PCui chlorate, ACFi is ammonium chloride. s AD indicates a trace amount of other additives, and AQ indicates water. Also, Mixture A and G are the electrolyte solution in Table 1, Mixture B and HFi electrolyte B, Mixture C and Mixtures F and L are mixtures prepared using electrolyte C, mixture E and Ku electrolyte E, and electrolyte F for mixtures F and L, respectively.

Table 2 Anode depolarization mixture 52 is prepared, and using this anode mixture, a paper-bound dry cell having the same structure and manufacturing method as conventionally known dry cells is assembled.

Here, first, the results of a model cell assembled discharge test conducted under the following conditions on the above-mentioned anode mixture used in such a dry battery station will be explained.

That is, the anode mixture to be tested 119 was placed on a zinc chloride plate with a diameter of 22 mm and an effective reaction area of 2 mm set in an acrylic container via a false separator, and the anode mixture was placed on the anode mixture under a pressure load of 20 mm. &1 shows the result of constant current discharge in an atmosphere at 25° C. through the cathode collector electrode and the anode collector in close contact with the cathode zinc plate. In other words, this is when the model cell is continuously discharged at a constant current of 6 ic at 121 mA, and the discharge current of the zinc cathode and anode mixture is ? W degree is 61mA each
/aJ, equivalent to 110mA/fl2. The results are shown in Table 3.

As can be seen from this result, I: Na0 of inorganic perchlorate
In the case of an electrolytic solution containing J04 or Zn(0204)1, an effect on super-heavy load discharge characteristics is observed, but
In the case of other perchlorates, 1; is not observed. Also MaO
In the case of an electrolyte to which JO*t or Zn(O2O3)1 is added, when other perchlorates are added or when used in combination with fine electrolytic manganese dioxide compared to the known zinc chloride electrolyte I: The characteristic improvement rate is large when

Next, the dry cell according to this invention C2, that is, the same structure and manufacturing method as the conventional dry cell; thus, the results of the rapid discharge test of the paper-lined AA dry cell (No. R-6) will be explained. . Table 4C Comparison of characteristics of AA batteries according to this invention C and AA batteries using a conventionally known electrolyte when constant resistance continuous discharge is performed at a load of 1.330 to 1.00V in an atmosphere of 20°C. 90 Table 4 In Table 4, As Go Be III is an R-6 type dry pond using a wet anode mix of the same composition as that used in test g2 using the model test cell described above, and A is A good one uses a known Zn0h-based electrolyte and electrolytic manganese dioxide with an average particle size of 25 μm, a good one uses a known Zn0JB-based electrolyte and electrolytic manganese dioxide with an average particle size of 5 μm, and B uses an electrolyte with WaOJO4 added. Average particle size 25μ
s RFi Na using electrolytic manganese dioxide
An electrolytic solution containing OJO4 and electrolytic manganese dioxide having an average particle size of 5 μm were used. It is something. From Table 4, it can be seen that the properties were the best when the electrolytic solution containing M&CJO4 and fine electrolytic manganese dioxide were used in combination in the present invention.

Table 5 shows 311 of the electrolytes A, B, and F among the electrolytes (Table 1).
The results of a corrosion test conducted by immersing a zinc plate in each case are shown below. Zinc test piece Fin as test condition
7 X 22. Owφ (reaction area 7.60j) is 121
1-After ultrasonic cleaning in KOH, 0.2sv (#)/
This is the value obtained after 360 hours at a test temperature of 45°C. In case 6: of B, no crystalline precipitates are observed, but when using electrolyte ν, g'
Precipitation of fine, colorless, poorly soluble crystals was observed.

As can be seen from Table 3.4.5 of the Examples, zinc chloride ti was mixed with an electrolyte solution containing mainly zinc chloride and an electrolyte solution to which sodium perchlorate was added.
The industrial value of the present invention is extremely great, as it shows a corrosion-proofing effect even against cathode zinc I. .

Although this invention has been explained using a paper-lined cylindrical battery, it is also possible to use a paste-type cylindrical battery as well.
Le Clancier type button battery.

It can also be used in flat dry batteries with an ultra-thin structure (so-called sheet batteries, etc.) ◇ Name of patent applicant

Claims (1)

[Claims] In dry battery C2, which uses manganese dioxide as an anode active material, zinc as a cathode active material, and zinc chloride as a main electrolyte, the electrolyte contains sodium perchlorate, and the manganese dioxide has an average particle size (5p). A dry battery characterized by being made of electrolytic manganese dioxide with a density of 1.0 m or less.